Horizontal line or pink square patches appearing on screen
I'm getting a very narrow horizontal line appearing across my screen - probably only a few pixels wide, and usually going across most of the screen (sometimes all the way, but usually more like 3/4's or a bit more). The location it appears varies, and overall I get a line this way more than half of the time.
I'm also getting very brief square pink patches that appear and quickly disappear - they are maybe 1 to 2 inches wide and the same high. They seem to appear most often when I'm changing a page view, for example opening a new browser tab or switching from one tab to another, or opening/closing a new application, etc.
Can anyone help me figure out just what is going on?
MacBook Pro, Mac OS X (10.5.8)